The instant invention relates to wafer-type check valves which are adapted to be received between a pair of pipeline flanges and more particularly, to such valves which are of substantially the same diameter as the flanges between which the valve is received.
The usual wafer-type check valve comprises a substantially annular valve body having a valve means or clapper pivotally mounted on the body. The body includes an annular seat against which the clapper is urged when pressure on the downstream side of the valve exceeds pressure on the upstream side, thus permitting fluid flow only from the upstream to the downstream side of the valve.
The usual pipeline flange is substantially annular in shape and extends radially outwardly from the outer diameter of the pipe on which it is mounted. The face of the flange is normal to the longitudinal axis of the pipe and includes eight axial bores therethrough which are equally spaced about the flange in 45.degree. intervals. Threaded studs may thus be used to connect the flange on one pipe to a flange on another pipe for forming a pipeline or may be used to sandwich a wafer-type check valve between the flanges.
Normally, the diameter of the check valve for a given size of pipe is smaller than the diameter of the flange for the pipe in question. Thus, when the check valve is received between the flanges and its axis is aligned with the pipeline axis, threaded studs may be inserted through the opposing flange bores without hitting the check valve. In another words, the diameter of the check valve is less than the diameter of a circle passing through the axis of each flange stud bore.
The instant invention comprises an annular ring or jacket having an upstream face and a downstream face and a central bore therethrough. A wafer-type check valve having an upstream and a downstream face is received within the central bore with the check valve and jacket upstream faces being substantially planar and the check valve and jacket downstream faces being substantially planar when the check valve is so received. A plurality of axial stud bores are spaced about the circumference of the jacket for alignment with corresponding flange stud bores when the jacket is received between a pair of opposing flanges.